rainboom posted a picture with them in it
36 total
18 are limits- 9first and 9last
3 are game progression- end disc 1, 2, 3
4 are materia related-knights of the round, bahumut zero, master one and master all
1 gil related- 99,999,999
1 level related- lvl 99 with anyone
2 for optional characters- vincent and yuffie
4 for defeating weapons- ruby emerald, diamond and ultima
2 for battle square- enter fight, win a fight
1 for chocobo- get a gold